For example, a driving part of an industrial robot or a commercial robot, for example, a cable used in wiring an arm part, is loaded with cyclic bending while driving an arm, and a cable used in wiring a door part of an automobile is loaded with cyclic bending while opening or closing a door. For this reason, in a cable loaded with cyclic bending, a conductive wire resistant to cyclic bending (hardly fractured) is used instead of a normal conductive wire. In addition, the conductive wire with a smaller diameter is less liable to be fractured by cyclic bending, so that, in a conductive wire of a cable, a stranded wire formed of a plurality of thin wires is used rather than a solid wire.
Further, as a conductive wire that is resistant to cyclic bending load, for example, such that the number of cycles to fracture (fatigue life) is 50,000 times or more when the conductive wire is subjected to cyclic bending of ±0.15% strain oscillation at normal temperature, Patent Literature 1, for example, discloses an aluminium alloy wire material containing 0.1 to 0.4 mass % of iron, 0.1 to 0.3 mass % of copper, 0.02 to 0.2 mass % of magnesium, 0.02 to 0.2 mass % of silicon, and 0.001 to 0.01 mass % of a combination of titanium and vanadium, wherein a crystal grain size in a vertical cross section in a wire drawing direction is 5 to 25 μm.
On the other hand, as an aluminium series conductive material having a smaller weight and being excellent in heat resistance, tensile strength, and electric conductivity. Patent Literature 2, for example, discloses an aluminium alloy containing 0.1 to 0.3 mass % (wt %) of scandium.
Also, as one in which the heat resistance of an aluminium alloy containing scandium is further improved, Patent Literature 3, for example, discloses an aluminium alloy containing 0.1 to 0.4 mass % of zirconium and 0.05 to 0.3 mass % of scandium, which is produced by performing a heat treatment after a plasticizing work; Patent Literature 4, for example, discloses an aluminium alloy containing 0.1 to 0.5 mass % of zirconium and 0.05 to 0.5 mass % of scandium, which is produced by performing a cold work after a heat treatment; and Patent Literature 5, for example, discloses an aluminium alloy containing 0.1 to 0.5 mass % of zirconium and 0.05 to 0.5 mass % of scandium, which is produced by performing a cold work, thereafter performing a heat treatment, and then performing a cold work again.